Walker kept a high strikeout rate, but also saw his walk-rate, which was already on the verge of being too high, rose another tick. Miller spent most of the season under the Mendoza line at the plate. His second half of offense and full season of quality defense made him worth 1.4 WAR in about three-quarters of a season’s worth of plate appearances. Miller posted a 122 wRC+ in the second half, which were it over the course of a full season would have been better than Desmond has posted in each of the last two years.

Desmond has also seen his strikeouts rise to an alarming level. Having hovered under a 23 percent strikeout rate for his entire career, Desmond spiked to more than 28 percent last year. I’m not going to claim to have seen a bunch of Ian Desmond last year or even earlier in his career, but often times this increase is a trait synonymous with reduced bat speed. Desmond’s glove is still very good, he’s been worth nearly 30 runs more than the average shortstop in the past three years. Desmond is 29 years old, and as a shortstop who has hit 69 homeruns in the past three years, he figures to get paid quite a bit once he hits free agency. This all points to the Mariners not having a great chance to gain any value beyond 2015 apart from the draft pick they’d receive after tendering Desmond a qualifying offer – unless of course Desmond collapsed or got injured and wasn’t worth a qualifying offer any longer.

Zimmermann is a pitcher who does a lot of things that are sustainable and valuable, if not extremely flashy. Zimmerman has good velocity on his fastball, averaging 93.8 MPH in 2014, but throws it more than 70 percent of his pitches. Zimmermann struck out 8.2 batters per nine innings in 2014, walking 1.31, which was good for an elite-level 6.28 strikeout to walk ratio. Zimmermann isn’t a guy relying on a favorable home ballpark or a strange uptick in luck. His fastball rate means that his .291 career BABIP against is probably legitimately caused by Zimmermann allowing quality contact pretty often. Zimmermann isn’t the kind of groundball pitcher that we’d expect to have large swings in BABIP based on quality of infield defense and luck. Rather, Zimmermann is a fly ball and strikeout guy, and one that doesn’t walk many hitters.

The Mariners had the opportunity to trade for two good major leaguers, but in order to do that, the Mariners would have had to give up two guys who may be good major leaguers. And while the hope of prospects developing can be equally valuable and crippling, Miller is projected for 2.3 WAR next year, and while Walker is projected to be essentially replacement level, he’s got upside of a legitimate ace.

Both Zimmermann and Desmond are projected for exactly 2.9 WAR in 2015. While a 3.5 WAR marginal gain would be considerable, and perhaps the deciding 3.5 WAR between the Mariners and a playoff appearance, that doesn’t mean that this trade is the best way to acquire those wins. All this without mentioning the actually dollar cost – Desmond and Zimmerman will combine to cost $27.5 million in 2015, which in itself would be about an even money investment in terms of dollars per win.

The Mariners have enough holes on their roster that they could receive marginal gains of substance at any outfield position, first base, or in a rotation slot without breaking the bank or pawning their prospects.